819
FXUS65 KBYZ 240033
AFDBYZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
633 PM MDT TUE JUN 23 2026
KEY MESSAGES
- MOSTLY DRY WITH SEASONABLE TEMPERATURES WEDNESDAY.
- GOOD CHANCE FOR PRECIPITATION (50-90%) THURSDAY, WITH A CHANCE
(10-15%) FOR A FEW STRONG TO SEVERE THUNDERSTORMS EAST OF
BILLINGS.
- ANOTHER CHANCE (40-70%) FOR SHOWERS AND THUNDERSTORMS FRIDAY
AFTERNOON AND ESPECIALLY FRIDAY NIGHT. A FEW STRONG STORMS ARE
POSSIBLE.
- WEEKEND STORM SYSTEM IS TRENDING DRIER AND WINDIER. SATURDAY
STILL SHOWS A GOOD CHANCE FOR WIDESPREAD PRECIPITATION (50-90%)
BUT SUNDAY ONWARD IS TRENDING MUCH DRIER. STILL TIME FOR CHANGES
TO THIS SYSTEM SO STAY TUNED TO THE FORECAST THIS WEEK.
UPDATE
SATELLITE IMAGERY SHOWS A DRY/CONFLUENT WNW FLOW ALOFT. LEE SIDE
SURFACE HIGH OF 1023MB IS SEASONABLY HIGH AND TODAY WAS COOL AND
STABLE. UPSTREAM, THERE IS A SHORTWAVE MOVING THRU WA WHICH WILL
LEAD TO INCREASING MID AND HIGH CLOUD FROM THE WEST TONIGHT. LOW
LEVELS REMAIN DRY BUT THERE IS SOME MID LEVEL MOISTURE AND VERY
ELEVATED INSTABILITY ASSOCIATED WITH THIS WAVE, SO WE COULD SEE
SPOTTY LIGHT SHOWERS OR SPRINKLES BY WEDNESDAY MORNING. HIGH RES
MODELS NOT SHOWING QPF BUT HAVE RAISED POPS A BIT OVER THE
MOUNTAINS STARTING AT 12Z, WHEN MODELS SHOW LARGE SCALE ASCENT
INCREASING. GREATEST CHANCE OF SHOWERS OR WEAK T-STORMS TOMORROW
AFTERNOON WILL BE OVER MOUNTAINS/FOOTHILLS. MOST OF THE AREA WILL
BE DRY OVER THE NEXT 24HRS. OTHERWISE, IT WILL BE ANOTHER QUIET
NIGHT W/ COOL TEMPS, AND MAYBE LOCALIZED FOG IN FAR NORTHEAST
VALLEYS (BETTER CHANCES OF THIS ARE IN NORTHEAST MT, HOWEVER).
SLIGHTLY COOLER THAN NORMAL TEMPS CONTINUE TOMORROW. JKL
DISCUSSION
THROUGH NEXT TUESDAY...
A QUIET SUMMER DAY TODAY AND TOMORROW. A 1020MB SURFACE HIGH AND
DRY NORTHERLY FLOW OVER THE AREA THIS AFTERNOON WILL KEEP MOSTLY
SUNNY SKIES IN PLACE TODAY. HIGH PRESSURE SLIDES EAST TONIGHT
WHICH WILL ALLOW SOUTHEASTERLY WINDS TO DEVELOP BEFORE SUNRISE,
COULD PRODUCE PATCHY FOG IN SPOTS EARLY TOMORROW MORNING, BUT
SHOULDN'T POSE MUCH OF AN IMPACT. WEAK RIDGING BUILDS OVER THE
AREA WEDNESDAY. THIS WILL SUPPRESS CONVECTION DURING THE DAY FOR
MOST OF THE AREA. SOUTHEAST WINDS UPSLOPING INTO THE SOUTHERN
MOUNTAINS MAY BE ENOUGH FOR A FEW AFTERNOON/EVENING SHOWERS AND
MAYBE A THUNDERSTORM ALONG THE SOUTHERN STATE LINE, BUT OVERALL A
GOOD DAY TO GET OUTSIDE AND ENJOY A GOOD DEAL OF SUN AND
TEMPERATURES IN THE MID 70S.
THURSDAY IS SHOWING A GOOD CHANCE FOR PRECIPITATION ACROSS THE
AREA, AND A MARGINAL RISK (10-15% CHANCE) FOR SEVERE STORMS,
MAINLY EAST OF BILLINGS. THE SET UP IS SIMILAR TO MONDAY WHERE A
VERY MOIST LOW LEVEL SOUTHEASTERLY FLOW WILL SET UP OVER THE AREA.
SHOWER CHANCES OVER EASTERN WYOMING INTO SOUTHEAST MONTANA
INCREASE LATE WEDNESDAY NIGHT AS THE LOW LEVEL JET PUSHES INTO
OUR AREA, DRAGGING RAIN MOISTENED AIR THIS DIRECTION. PWATS
INCREASE TO AROUND 1.25 INCHES, SHEAR PROFILES SHOW 40-50KTS OF
BULK SHEAR, AND WIDESPREAD MLCAPE VALUES OF 1000J/KG (WITH A
CORRIDOR OVER 2000J/KG OVER BIG HORN, SHERIDAN, ROSEBUD, AND
POWDER RIVER COUNTIES) ALL POINT TO A GOOD SETUP FOR STRONG TO
SEVERE THUNDERSTORMS THURSDAY AFTERNOON AND EVENING. THERE IS ALSO
A DECENT SHORTWAVE MOVING IN FROM THE WEST AT A FAVORABLE TIME TO
HELP LIFT THE ATMOSPHERE AND BECOMING A FOCUS FOR A MORE ORGANIZED
STORM THREAT. A FORECAST STORM MOTION OF UNDER 12MPH COMBINED WITH
THE HIGH PWATS POINTS TO THE POTENTIAL FOR LOCALLY HEAVY RAINFALL
WITH ANY THUNDERSTORMS AS WELL.
THE FLY IN THE OINTMENT THOUGH IS THE SAME AS MONDAY, CLOUD COVER
AND ONGOING LIGHT SHOWERS. NBM IS SHOWING 60 TO 90 PERCENT CLOUD
COVER ACROSS MOST OF THE AREA STARTING EARLY IN THE MORNING AND
CONTINUING THROUGH THE DAY ALONG WITH ISOLATED TO SCATTERED WEAK
SHOWER ACTIVITY SPREADING NORTHWARD WITH THE INCREASING
SOUTHEASTERLY LOW LEVEL JET. CURRENT FORECAST SHOWS HIGHS MAINLY
IN THE MID 70S THURSDAY AFTERNOON, BUT THE CLOUDS/SHOWERS COULD
TAKE SEVERAL DEGREES OFF THAT FORECAST AND DROP TEMPERATURES WHATS
NEEDED FOR STRONGER CONVECTION. SO, WRAPPING UP, THURSDAY SHOWS
STRONG (60-90%) CHANCES FOR PRECIPITATION (LOCALLY HEAVY RAINFALL
POSSIBLE) AND THE INGREDIENTS FOR STRONG TO SEVERE STORMS, BUT A
LIMITING FACTOR IN THAT CLOUD COVER AND ONGOING SHOWER ACTIVITY
COULD LIMIT THE HEATING NECESSARY TO ALLOW FOR STRONG STORM
DEVELOPMENT. CURRENT SPC MARGINAL RISK SEEMS APPROPRIATE FOR NOW
GIVEN THE CONDITIONAL STORM SETUP.
FRIDAY HAS TRENDED COOLER OVER THE PAST SEVERAL DAYS AS THE LARGE
ROBUST PACIFIC STORM SYSTEM HAS WORKED CLOSER TO THE AREA IN THE
MODELS OVER TIME. ITS STILL LOOKS TO BE THE WARMEST DAY OF THE
WEEK BUT HIGHS ARE NOW IN THE LOW TO MID 80S INSTEAD OF 90S. WITH
AN EASTERLY LOW LEVEL FLOW ESTABLISHED AND HOLDING SOUTHWEST WIND
ALOFT THE DOWNSLOPE FACTOR IS GREATLY REDUCED AND PRECIPITATION
CHANCES ARE INCREASING DURING THE AFTERNOON PERIOD, ESPECIALLY
OVER WESTERN MOUNTAINS AND FOOTHILLS LOCATIONS. BY FRIDAY EVENING
PRECIPITATION CHANCES ARE AROUND 60 PERCENT ACROSS THE FORECAST
AREA. NCAR ML/AI SEVERE THREAT GUIDANCE SUGGESTS A 10-30% CHANCE
FOR SEVERE STORMS FRIDAY, AND HAS THE THREAT FURTHER WEST AND
NORTH THAN ON THURSDAY.
FOR THE WEEKEND, THE CORE OF THE STORM SYSTEM IS SHOWING SIGNS IN
THE MODELS OF DROPPING INTO SC IDAHO SUNDAY NIGHT THEN TAKING A
SHARP NORTHERLY TURN AND TRACKING TO THE MONTANA/ALBERTA/SASK
BORDER BY MONDAY MORNING. THIS TRACK IS NOT OPTIMAL FOR A MULTI-
DAY PRECIPITATION EVENT OVER OUR AREA, PARTICULARLY THE FURTHER
EAST IN OUR AREA YOU ARE, AS IT PUTS OUR AREA ON THE DRY GUSTY
DOWNSLOPING WINDS PORTION OF THE SYSTEM. SATURDAY STILL LOOKS WET
FOR MOST OF THE AREA BUT AREAS ALONG THE MT/WY BORDER FROM
SHERIDAN EAST ARE TRENDING DRIER OVER THE PAST SEVERAL MODEL RUNS.
SUNDAY IS LOOKING PRETTY DRY ACROSS THE AREA OUTSIDE OF THE
WESTERN MOUNTAINS AND FOOTHILLS IN THE NBM, WITH MAYBE A FEW
HUNDREDTHS OF AN INCH DURING THE DAY. MONDAY IS NOW BASICALLY DRY
WITH THE MEAN STORM CENTER CONTINUING TO TRACK NORTH THROUGH
CANADA. THE DRYING TREND IS THANKS TO THE MODELS LOOKING TO
STRENGTHEN A STRONG SUBTROPICAL HIGH PRESSURE SYSTEM OVER THE
LOWER MISSISSIPPI VALLEY THE RIDGES NORTH THROUGH THE GREAT LAKES
AND BLOCKS THE UPPER LOW FROM MOVING EAST AND PUSHES IT NORTH.
THERE ARE STILL DISAGREEMENTS IN THE MODELS WITH ENSEMBLE CLUSTERS
SHOWING THE CANADIAN, ECMWF, AND GFS ENSEMBLES ALL CLUSTERING INTO
THEIR OWN SOLUTIONS. UNTIL THE MODELS GET ON A SIMILAR IF NOT THE
SAME PAGE ITS HARD TO PUT TOO MUCH STOCK INTO ANY GIVEN MODEL RUN
RIGHT NOW FOR SAT-TUE. THAT SAID, THE TREND IS FOR A SHORTER
LIVED STORM SYSTEM AND DRIER OVERALL FORECAST FOR THE WEEKEND
INTO EARLY NEXT WEEK. IF YOU HAVE OUTDOOR PLANS THIS WEEKEND
PLEASE CONTINUE TO KEEP UP WITH THE LATEST FORECASTS AS DETAILS
SHOULD COME INTO BETTER FOCUS OVER THE NEXT FEW DAYS. CHAMBERS
AVIATION
PATCHY FOG MAY IMPACT LOCATIONS EAST OF BILLINGS WEDNESDAY MORNING
(09-15Z) INCLUDING TAF SITES KMLS AND KSHR. STARTING AROUND 18Z
WEDNESDAY, ISOLATED (30-40%) SHOWERS AND THUNDERSTORMS MAY IMPACT
THE ABSAROKA/BEARTOOTH AND BIGHORN MOUNTAINS. WIND GUSTS OF
20-30 KTS WILL IMPACT KLVM STARTING TONIGHT AND LASTING THROUGH
THE DAY WEDNESDAY. TORGERSON
PRELIMINARY POINT TEMP/POPS
WED THU FRI SAT SUN MON TUE
-----------------------------------------------------------
BIL 051/074 054/075 054/083 057/075 052/068 050/073 051/080
00/B 16/T 22/T 69/T 86/T 22/T 21/U
LVM 045/075 047/073 048/079 048/068 042/059 040/065 042/072
01/B 28/T 23/T 69/T 98/T 45/T 21/U
HDN 048/075 051/076 052/085 056/078 051/071 046/075 049/082
01/B 18/T 41/B 67/T 86/T 32/W 21/U
MLS 047/073 050/076 053/081 059/079 055/072 050/073 051/080
00/B 05/T 62/T 76/T 76/T 42/W 21/U
4BQ 047/072 051/072 053/082 060/081 056/075 051/076 052/083
02/W 38/T 71/B 55/T 75/T 42/W 11/U
BHK 043/071 046/073 050/077 057/082 053/076 048/074 049/080
00/B 03/T 61/B 65/T 75/T 42/T 21/U
SHR 045/072 049/072 049/082 053/076 048/071 043/074 044/080
02/T 4+/T 62/T 47/T 75/T 42/T 11/U
BYZ WATCHES/WARNINGS/ADVISORIES
MT...NONE.
WY...NONE.
WEATHER.GOV/BILLINGS
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